If you want to make changes you need to move the car over to moddev, make any changes you want, then re package the car. Sent from my Nexus 4 using Tapatalk 2
After start, all okay, look: View attachment 7411 I have tested somthing: Started Mas2.exe and load the corvette: View attachment 7408 It looks like this: View attachment 7409 Then, i export the engine.ini to Desktop, import it direktly without changes and save it. And that shows the modmanager: View attachment 7410 I think the mistage comes at saving the file.
Has it been removed in the latest versions? I can't see it in my turbo cars, and I'm sure new engine model is working as turbos are implemented.
Bump. I started fiddling with the turbomodel again and I have the same problem as LeStrat. Turbohud is gone. Is there any way I could get the data to a logfile from moddev, like the Motec plugin? What I'd need for hassle free testing is everything the turbohud had and preferably generated Nm either from crank/flywheel or wheels. A poor man's way in finding what your max torque is now setting clutch strength around max and then tweaking your settings so that you'll stay under it.. Which is pretty damn stupid
'Alt'+'=' will cycle through some displays including engine info. Sent from my Nexus 4 using Tapatalk
Guys, the back torque...... I played around with it and making it more (I go from the point that it's called negative because it works against the engine when coasting) and giving it more, makes the car faster?? It was around -77,5 and I made it -177,5 That would mean the rotating internia is heavier and/or the compression is higher. The last one could/would make the car go faster, the first would not. Am I missing something here? Also, the "VolumeFract".......is there something more know about that one now? Is it really a torque multiplier at given throttle standings? So if I would want the car to respond later to the throttle, the line would go from something like this: 0.0 0.2 0.4 0.6 0.8 1.0 to something like this: 0.0 0.1 0.2 0.3 0.6 1.0 Right?
While more negative "back torque" will allow the car to slow more quickly which has great influences on braking zones, engine inertia is specified elsewhere. They are different. Heavier rotating masses will affect inertia. I still have a hard time with "back torque", my current understanding is that it is the work done by the piston pulling against a closed throttle plate. The notes on Volume Fract as listed in this thread seem logical. I have no reason to believe it is anything other than a multiplier.
Think of backtorque in the following way. When you finish assembling an engine you can't move it with your bare fingers, there is significative amount of "torque" that you must apply in order to move it, so assume that the engine has an initial backtorque for example of 10 Newtons and that would be the minimal ammount of backtorque for that engine (when it's off). When you start up and rev up and engine backtorque will increase in (almost) a linear way. For better understanding, Btq (Backtorque) is a force that would counter-act the rotational and (accumulated) kinetic force inside the engine, higher btq values will minimize engine efficiency but is not directly linked to performance. Setting higher values will help to reduce RPM when coasting (specially if the gear is uncopled - "neutral"), so btq will play it's role in a logaritmic way with the engine inertia. I use a simple formula to calculate Btq: Code: InitialBrakeTorqueAddedNm = -10 to -20 //N.m DisplacementCm3 = 1000 //cm3 "1 litre = 1000 cm3" CompressionRatio = 10.5 //"10.5 = 10.5:1" CompressionEfficiency = 0.9 //pct "0.9 = 90%" MaxBackTorque = ((InitialBrakeTorqueAddedNm + (0.000004344 * DisplacementCm3 * RPM * ((CompressionRatio ^ 0.2857) - 1)) * CompressionEfficiency) * (-1)) Or if you have extra dyno-info you could also use a more advanced formula like this (car data in SI, change them accordingly): Code: InitialBrakeTorqueAddedNm = -10 to -20 N.m EngineVolumeM3 = 0.003 //engine volume in m^3 (=1e-3 liter) StrokeM = 0.0457 //stroke in m, typically 0.04-0.1 m Cylinders = 6 //number of cylinders CompressionRatio = 12.5 //compression ratio VolumeIntakeManifold = 0 //volume of the intake manifold mIn = 135.968 K = 1.4 //kelvin temperature AmbientAirPressurePa = 100000 //pascal c = 1 - K vd = EngineVolumeM3 / Cylinders //displacement/swept volume vc = vd / (CompressionRatio - 1) //crearance volume MaxBackTorque = ((Cylinders / c) * ((vc + VolumeIntakeManifold / CompressionRatio) / ((VolumeIntakeManifold + vc) ^ c)) * ((VolumeIntakeManifold + vc + vd) ^ c - (VolumeIntakeManifold + vc) ^ c) - EngineVolumeM3) * AmbientAirPressurePa / (4 * Pi) Note comments starts with //
Plus the force of a piston must overcome for entering in the carter oil, plus how tightly the engine is assembled (street engines are softer than race), plus a restrictive exhaust manifold, etc. etc. etc.
I'm going to play skeptic contrarian here, so bear with me. How do you know "engine backtorque will increase in (almost) a linear way"? I've not found any tech/scholarly documents with BT measurement. I've not 1 dyno to show what it should or shouldn't look like. Quite honestly I don't think you can build a formula to model it, in much the same way you cannot generate the torque curve for a full throttle dyno pull. It is something characteristic of the individual car, and must be measured. I've seen your simple formula, how did you arrive at this? I do not understand this statement: "Plus the force of a piston must overcome for entering in the carter oil" Wouldn't engine assembly tolerance only affect friction? cheers, lp
Drawn the btq values from ISI engines and you would see what I mean with "almost" linear. Some things that I've stated it's a simplified reply to Navigator to keep him going, it's nice to see you want to go deeper on this subject so this is the doc for you "Real-time brake torque estimation for internal combustion engines" Javier Franco, Matthew A. Franchek, Karolos Grigoriadis If you have taken measures then you have values and you must use them, otherwise you will likely attempt to build those values using a formula (that does calculations with the standart deviation approach) which is better than inputting random values. Also STDDEV could be used to compute patterns like those found among engine manufacturers and brands. That's why I think it's possible. It could result exactly like the real thing ? maybe, but if not then is pretty close to. I've got that formula by reverse engineering another sim So don't ask me in public. Neither do I pardon my spanglish, It's my failed attempt to transcript this oil setup. I don't understand what you mean, if you could develop it some more I'll be glad to answer.
Thanks, first link will keep me busy for a bit, and is exactly what I've been looking for. edit: On second thought maybe not, that is for diesel. Which IIRC does something differently with intake at closed throttle. edit 2: It also appears that this is just an estimate of engine output, Whereas BHP=brake horsepower (brake is from the method used to measure) Still looking for papers about back torque.
The major root cause for "back torque" from my point of view are the forces necessary to compress the gas in the cylinder and overcome the internal friction losses in the combustion engine. My recommendation is to google for "compression ratio" and "internal friction" Compression ratio is well explained at wikipedia and obviouslydepends on the engine concept (typical values of ICE are between 10:1 to 14:1). The internal friction is a little mor sophisticated. Found an SAE paper which looks interesting buts not for free http://papers.sae.org/2012-36-0303/ My guess in regard the force a piston must overcome for entering the carter oil is that the losses due to the crankshaft running through the motor oil is resulting in losses as well - should be covered by internal ICE losses but I'm not sure there. To get the back torque on the crank shaft you need to determine the resulting forces at every RPM value and torque is Force*distance. Whether internal losses is linear correlating with RPM I have my doubts - but in a realtime model you need to simplify anyway and very likely the failure is negligible. Sent with Tapatalk
We just need to lure [MENTION=2449]Michael Borda[/MENTION] into this thread, maybe he can give us a heads up which direction to look.
@lordpantsington More braking torque literature ftp://ftp.energia.bme.hu/pub/Tananyagok-archivuma/BSc-kepzes/Interan%20Combsution%20Engines-Temp.pdf Pages 20,34,37 http://www.personal.utulsa.edu/~kenneth-weston/chapter6.pdf Pages 12,13,14,15 http://www.rmcet.com/lib/E-Books/Mech-auto/Engineering%20Fundamentals%20of%20IC%20Engines%20(WW%20Pulkrabek).pdf From page 65
Thanks, but I'm not looking for papers on the fundamentals of ICE. Brake torque is just the torque of the engine (with throttle). I prefer to use the term back torque, or engine braking torque (no throttle). I did find this last night: http://www.fsae.com/forums/showthread.php?11430-Engine-Braking-Torque (post 9)
Still; it is strange that back torque (or coast torque in the engine.ini) makes the engine faster if given more(!) There are more forces you could take for "engine internia" > internal friction OR the mass of the rotating parts itself...... The last one, could be just as easily be the back torque....... Lets say the crankshaft is heavier; the engine revs up slower, but will maintain speed more>making it faster WHEN it goes. But that's actually what internia does btw. Ehm, I don't know what I wanted to say anymore, hehe.......going to read some more, thanks!
I've recently developed a little tool for engine building in rF2 and I thought I'd share it here. I built it around previous engine models I've developed and adopted it to rF2's implementation. Since the rF2 model is not fully documented there are some differences but it's close enough for me at least. Some comments: -Turbo map fitting is aimed at Garrett turbos atm -AFR effects are not taken into account. So the model is always running at lambda=1.0 -I only included a simple torque curve and throttle map. But you can modify it with your own data under "engine" tab. -I haven't bothered explaining too much in the excel sheet since it started out as a quick and dirty calculation. But if you have any questions I'll try to answer them. Download here View attachment 12744 View attachment 12745 View attachment 12746 View attachment 12747 View attachment 12748
